Yes. You do not have to remove the PlugBug from your Mac's AC adapter if you just want to plug that in. I'm not sure where you read it will take longer but that is incorrect. My 15" MacBook Pro takes the same amount of time to charge whether I use my PlugBug or not.

I do not know why one could not use either their (iPhone or iPad) iOS charger on the PlugBug's AC output for one USB output power source (iPhone or iPad, resp.) and the PlugBug's USB output power source for charging the 2nd iOS (iPhone, iPad, or iPod) device. Why not?

There would be no reason why it would not work with the new iPhone 5 "lightning cable". The new cable works on the same 5 volt signal as its predecessor (iPhone 4-4S). It still connects via universal serial bus or "USB" connector. I hope this helps clarify the question.

Unfortunately yes if you are going to use it in Europe. The PlugBug part has the AC power prongs and they are configured for the US type. I guess you could just use a plug converter to change the plug config as the power supply will correctly convert it to the right voltage and frequency.

I am travelling to Canada next month and wish to take my iPad2 & iTouch4 with me. Will this device charge both at the same time, and does it fit into a Canadian power socket (which is similar but not identical to the USA)?

US and Canadian power outlets are identical. There's no need for any special adapter. This particular device is meant to attach to a MacBook AC adapter to provide a single USB connection. What you are looking for is an AC adapter that has two USB inputs to charge an iPad and iPod Touch at the same time. Those can be easily found online cheaply.

There is a USB outlet as well as a component for you to charge your Macbook. So there is no reason why it cannot charge your iPad 4... I have charged an MBA and iPhone 5 successfully, at the same time.